I'm hoping that this was sarcastic and all, but what the hell, I was a fully-grown adult on September 11, 2001 and I know modern history gets left out of school curricula a lot, so ...
Technically, no, they used airplanes.
Technically, yes, they hijacked the airplanes with box-cutting knives.
But ultimately, no, they hijacked the airplanes by leveraging the social contract around hijacking.
I know it sounds kinda wild that there would be a social contract around fucking hijacking, but really, there was, because hijacking airplanes was just a fancy form of hostage-taking to negotiate some kind of desired outcome. Sometimes (often) it was just straight up money. Other times, political demands. Very, very rarely was anyone killed or seriously harmed in an airplane hijacking, because mostly the hijackers wanted to get their money/concessions/political prisoners freed/etc and *not kill anybody* so they could just vanish and nobody would hunt them down.
So the official stance on how to handle a hijacking as pilot/crew was ... "let them". Offer no resistance, do what they ask. Same for how to survive an airplane hijacking as a passenger. Cooperate and let them negotiate with the trained negotiators who could give them what they wanted.
The 9/11 hijackers played it like a "normal" airplane hijacking and so the pilots, crews, and passengers followed the script, like smart people. Like, seriously, box-cutters?
Unfortunately for them, the 9/11 hijackers changed the second act. They included trained pilots, so they could fly the planes themselves, without relying on the airline pilot (which hijackers usually did). That let them redirect to their choice of targets without any warning from the airline pilot - the Twin Towers, the Pentagon, and [presumed] the White House.
I note [presumed] there, because that flight didn't make it to its target. It did get hijacked, just like the others. They replaced the pilot with their own, just like the others. But that flight was just later enough than the others that they got word about the Towers going down, and they realized the old script had gone out the window. So they fought back and, well, that plane crashed in a field in Pennsylvania. None of them survived, but their target, whatever it was, was unscathed.
The TSA is a bullshit program whose entire purpose is a) security theater and b) conditioning the American population to accept surveillance and fascism.
George W. Bush, that festering turd of a president, can rightfully expect to roast in hell with scorpions stinging his face for eternity for what he did to *both* this country and the entire Middle East in response.
And the TSA and all that security theater? Didn't exist until after 9/11.